1. Field of the Invention
The present invention relates to a rubber layered structure, and more particularly to a structure for attaching to the periphery of openings of an automobile. The rubber layered structure includes an EPDM rubber base and a surface layer such as an ornamental layer or a layer for enhancing the slidability of window glass.
2. Description of the Related Art
EPDM (ethylene-propylene non-conjugated diene copolymer) rubber is widely used for automobile parts which require good resistance to weather, ozone, and heat. A variety of elements including an EPDM rubber base has been studied to attain pleasing designs and enhance functions such as slidability.
EPDM rubber is favorably applied to, for example, weather strips. Weather strips are attached to the periphery of door openings of automobiles to seal the openings so as to keep out rainwater, dust and noise.
EPDM rubber itself is, however, black and not visually pleasing. Accordingly, the EPDM rubber base is usually covered with an ornamental layer such as polyester or nylon cloth which has a color well matched with the automobile interior.
The manufacturing process for the rubber layered structure having an EPDM rubber base and a surface layer includes, for example, extrusion and vulcanization of the EPDM rubber base, buffing and de-greasing of the EPDM rubber base, coating with a primer and an adhesive, drying of the adhesive, application of the surface layer, and solidification of the adhesive.
The conventional process requires a number of steps noted above which results in a long production line, thus causing low productivity and high cost.
JAPANESE LAID-OPEN PATENT PUBLICATION No. Sho-58-158216 proposes a method in which a solvent adhesive including ethylene vinyl alcohol (EVA), nylon, or polyester is first applied on the surface on one side of a surface member. The adhesive side of the surface member is placed upon an extruded main body immediately after extrusion forming and is further pressed thereon with a roller. The internal heat of the extruded main body melts the adhesive, and the surface member is accordingly stuck to the extruded main body. This method, however, has certain disadvantages when used with such materials as an EPDM rubber base because no adhesives can securely stick to both the EPDM rubber base and surface layer material such as polyester.
Besides being used for weather strips to seal door openings, EPDM rubber is also used for a weather strip between a door sash and a window glass, which is generally called a glass run. A member for enhancing slidability of glass is stuck to a portion of the glass run facing the window glass, or alternatively, the portion is covered with a slidable material or flocking so as to enhance the slidability of the window glass. This rubber layered structure has the same problems as stated above for other weather strips, that is, low productivity and poor adhesive strength.